The system is constantly learning, so it "retunes" itself. We can infer epitopes from structure, but we found that data derived from known complexes is sufficient for our purpose.
Current version of EWS does not explicitly account for glycosylation. It is implicitly handled by the ML models, though.
For specificity, it is difficult to estimate. We know that for each of the named Variants of Concern, the signal from EWS was unmissable. Considering, that any new vaccine would need to go through a stringent approval process, I don't think that EWS should be a major determining factor in the process. However, it can certainly help resolve the doubts.